DNA has been found in samples that are claimed to be tens of millions of years old - Seven confirmed examples
This is how rapidly DNA degrades in different conditions:
Complete degradation: Generally, studies suggest that even under optimal conditions, DNA completely degrades within approximately 1-1.5 million years. This is an estimate and depends greatly on how favorable the conditions have been for DNA preservation.
Summary:
- Under optimal conditions, DNA can survive for up to hundreds of thousands of years, but complete degradation occurs within approximately 1-1.5 million years.
- In normal environments, DNA typically survives for thousands of years.
- In unfavorable conditions, DNA can become unusable within just a few hundred years.
Excerpt: "By comparing the specimens' ages and degrees of DNA degradation, the researchers calculated that DNA has a half-life of 521 years. That means that after 521 years, half of the bonds between nucleotides in the backbone of a sample would have broken; after another 521 years half of the remaining bonds would have gone; and so on.
The team predicts that even in a bone at an ideal preservation temperature of −5 ºC, effectively every bond would be destroyed after a maximum of 6.8 million years. The DNA would cease to be readable much earlier — perhaps after roughly 1.5 million years, when the remaining strands would be too short to give meaningful information."
This rapid rate of DNA degradation casts doubt on studies claiming that DNA has been recovered from samples as old as tens of millions of years:
"We report here the extraction of DNA from fossil leaf samples from the Miocene Clarkia deposit (17-20 My r old)"
https://pubmed.ncbi.nlm.nih.gov/1411508/
"DNA was extracted from the fossil termite Mastotermes electrodominicus preserved in Oligo-Miocene amber (25 million to 30 million years old)."
https://www.nature.com/articles/363677a0
"The Dominican amber deposits have yielded a wealth of information about organisms living ~ 25-40 million years ago in Hispaniola . We now report the extraction, amplification and sequencing of the chloroplast gene rbcL from a leaf of the extinct tree, Hymenaea protera Poinar (Fabaceae: Caesalpinioideae)"
https://pubmed.ncbi.nlm.nih.gov/23085295/
"These data are the first to support preservation of multiple proteins and to present multiple lines of evidence for material consistent with DNA in dinosaurs, supporting the hypothesis that these structures were part of the once living animals."
https://academic.oup.com/nsr/article/7/4/815/5762999
"Furthermore, isolated Hypacrosaurus chondrocytes react positively with two DNA intercalating stains. Specific DNA staining is only observed inside the isolated cells, suggesting endogenous nuclear material survived fossilization. Our data support the hypothesis that calcified cartilage is preserved at the molecular level in this Mesozoic material, and suggest that remnants of once-living chondrocytes, including their DNA, may preserve for millions of years."
https://pubmed.ncbi.nlm.nih.gov/7973705/
"DNA was extracted from 80-million-year-old bone fragments found in strata of the Upper Cretaceous Blackhawk Formation in the roof of an underground coal mine in eastern Utah. This DNA was used as the template in a polymerase chain reaction that amplified and sequenced a portion of the gene encoding mitochondrial cytochrome b."
https://www.nature.com/articles/363536a0
We report here the extraction of DNA from a 120–135-million-year-old weevil (Nemonychidae, Coleoptera) found in Lebanese amber, PCR amplification of segments of the 18S rRNA gene and the internal transcribed spacer, and the corresponding nucleotide sequences of their 315- and 226-base-pair fragments, respectively.
This is why I have no reason to believe in the theory of evolution.
